# US 2019/0316554 A1 · Fuel system for an internal combustion engine > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2019/0316554 A1 - Document ID: US20190316554A1 - Status: Published application - Kind: A1 - Application number: 16/317,468 - Filed: 2017-07-17 - Published: 2019-10-17 - Earliest claimed: 2016-07-18 - Assignees: Scania CV AB - Applicants: Scania CV AB - Inventors: Adam BERG; Kim KYLSTRÖM; Emil KYLBERG; Patrik FOGELBERG - Web page: https://patentgrep.com/patent/US20190316554A1 ## CPC - F02M 37/08: electrically driven - F02D 41/3082: {Control of electrical fuel pumps} - F02D 41/3809: {Common rail control systems (common rail apparatus F02M55/025, F02M63/0225)} - F02M 37/0047: {Layout or arrangement of systems for feeding fuel (fuel injection apparatus characterised by their conduits and venting means F02M55/00; fuel injection apparatus having a common rail F02M63/0225; arrangement of fuel conduits of low pressure fuel injection apparatus F02M69/462)} - F02M 37/18: characterised by provision of main and auxiliary pumps - F02M 37/36: with bypass means - F02D 41/221: {relating to the failure of actuators or electrically driven elements} - F02D 41/3854: {with elements in the low pressure part, e.g. low pressure pump} - F02D 2250/31: Control of the fuel pressure - F02M 37/24: characterised by water separating means - F02M 59/366: {Valves being actuated electrically} - F02M: SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF - F02D: CONTROLLING COMBUSTION ENGINES (vehicle fittings, acting on a single sub-unit only, for automatically controlling vehicle speed B60K31/00; conjoint control of vehicle sub-units of different type or different function, road vehicle drive control systems for purposes other than the control of a single sub-unit B60W) ## Abstract The present invention relates to a fuel system for a combustion engine, the fuel system comprising a low-pressure circuit comprising at least one fuel tank, at least one low-pressure fuel pump, a first fuel filter and a second fuel filter which is arranged downstream of the first fuel pump, and a high-pressure circuit comprising a high-pressure fuel pump. The high-pressure fuel pump comprises means to suck fuel from the low-pressure circuit and in case of failure in the at least one low-pressure fuel pump, to suck fuel from the low-pressure circuit and the fuel is arranged to by-pass the at least one low-pressure fuel pump and optionally, at least one of the first or second fuel filters, via at least one by-pass pipe comprising a check valve that prevents the flow of fuel back to the fuel tank. ## Claims ### Claim 1 A fuel system for an internal combustion engine, the fuel system comprising: a low-pressure circuit comprising at least one fuel tank; at least one low-pressure fuel pump; a first fuel filter and a second fuel filter which is arranged downstream of the first fuel pump; and a high-pressure circuit comprising a high-pressure fuel pump, wherein the high-pressure fuel pump comprises: means to suck fuel from the low-pressure circuit, and in case of failure in any of the at least one low-pressure fuel pumps, the high-pressure fuel pump is arranged to suck fuel from the low-pressure circuit and the fuel is arranged to by-pass the at least one low-pressure fuel pump via at least one by-pass pipe comprising a check valve that prevents the flow of fuel back to the fuel tank. ### Claim 2 (depends on 1) The fuel system according to claim 1, further comprising a common by-pass pipe with a check valve that prevents the flow of fuel back to the fuel tank is arranged to by-pass the at least one low-pressure fuel pump and at least one of the first or second fuel filters. ### Claim 3 (depends on 1) The fuel system according to claim 1, wherein both the first fuel filter and the second fuel filter are located downstream of the at least one low pressure fuel pump. ### Claim 4 (depends on 1) The fuel system according to claim 1, wherein the first fuel filter is arranged upstream of the at least one low-pressure fuel pump and the second fuel filter is arranged downstream of the at least one low-pressure fuel pump. ### Claim 5 (depends on 3) The fuel system according to claim 3, wherein fuel is arranged to by-pass both the defect low-pressure fuel pump and the first fuel filter via a by-pass pipe comprising a check valve, which check valve prevents the flow of fuel back to the fuel tank. ### Claim 6 (depends on 1) The fuel system according to claim 1, wherein the fuel is arranged to pass through both the first and second fuel filters, and wherein a check valve is arranged between the first and second fuel filters to prevent the flow of fuel from the second fuel filter back to the first fuel filter. ### Claim 7 (depends on 1) The fuel system according to claim 1, wherein the fuel system comprises a first low pressure fuel pump located upstream of a second low-pressure fuel pump and a second fuel tank, and wherein, in case of failure in at least one of the low-pressure fuel pumps, both low-pressure fuel pumps are arranged to be turned off and the fuel is arranged to by-pass both low-pressure fuel pumps via at least one by-pass pipe comprising a check valve, which check valve prevents the flow of fuel back to any one of the fuel tanks. ### Claim 8 (depends on 7) The fuel system according to claim 7, wherein both the first and the second fuel filters are located downstream of the first low pressure fuel pump and wherein the first fuel filter is located upstream of the second fuel pump and the second fuel filter is located downstream of the second fuel pump. ### Claim 9 (depends on 7) The fuel system according to claim 7, wherein the fuel is arranged to by-pass the first and second low-pressure fuel pumps and the first fuel filter via a common by-pass pipe comprising a check valve. ### Claim 10 (depends on 7) The fuel system according to claim 7, wherein the fuel is arranged to by-pass the first low-pressure pump and the second low-pressure fuel pump via a respective by-pass pipe, wherein a check valve is arranged downstream of the first fuel filter and upstream of the second filter, which check valve prevents the flow of fuel back to the fuel tanks. ### Claim 11 (depends on 1) The fuel system according to claim 1, wherein the means to suck fuel from the low-pressure circuit comprises at least one electrically controllable inlet valve. ### Claim 12 (depends on 12) The fuel system according to claim 12, wherein the high-pressure fuel pump comprises at least one electrically controllable inlet valve, wherein the inlet valve is arranged in an open position and the high pressure pump is arranged to suck fuel from the low-pressure circuit when the pressure of the fuel flow is lower than the pressure of the fuel flow during a normal operation of the internal combustion engine. ### Claim 13 (depends on 1) The fuel system according to claim 1, wherein in the high pressure fuel pump is driven by the internal combustion engine. ### Claim 14 An internal combustion engine comprising a fuel system, in turn, comprising: a low-pressure circuit comprising at least one fuel tank; at least one low-pressure fuel pump; a first fuel filter and a second fuel filter which is arranged downstream of the first fuel pump; and a high-pressure circuit comprising a high-pressure fuel pump, wherein the high-pressure fuel pump comprises: means to suck fuel from the low-pressure circuit, and in case of failure in any of the at least one low-pressure fuel pumps, the high-pressure fuel pump is arranged to suck fuel from the low-pressure circuit and the fuel is arranged to by-pass the at least one low-pressure fuel pump via at least one by-pass pipe comprising a check valve that prevents the flow of fuel back to the fuel tank. ### Claim 15 A vehicle comprising: an internal combustion engine; and a fuel system, in turn, comprising: a low-pressure circuit comprising at least one fuel tank; at least one low-pressure fuel pump; a first fuel filter and a second fuel filter which is arranged downstream of the first fuel pump; and a high-pressure circuit comprising a high-pressure fuel pump, wherein the high-pressure fuel pump comprises: means to suck fuel from the low-pressure circuit, and in case of failure in any of the at least one low-pressure fuel pumps, the high-pressure fuel pump is arranged to suck fuel from the low-pressure circuit and the fuel is arranged to by-pass the at least one low-pressure fuel pump via at least one by-pass pipe comprising a check valve that prevents the flow of fuel back to the fuel tank. ### Claim 16 A method of operating the fuel system comprising: a low-pressure circuit comprising at least one fuel tank; at least one low-pressure fuel pump; a first fuel filter and a second fuel filter which is arranged downstream of the first fuel pump; and a high-pressure circuit comprising a high-pressure fuel pump, wherein said method comprises: identifying the functionality of the at least one low-pressure pump in the fuel system; in the event of good functionality of the at least one low pressure fuel pump, the at least one low pressure fuel pump is arranged to supply fuel from the at least one fuel tank to the high pressure circuit by operating the at least one low pressure fuel pump with an electric motor; or in the event of an identified operational disturbance in the at least one low pressure fuel pump: turning off all low pressure fuel pumps; arranging the flow of fuel to by-pass the at least one low-pressure fuel pump via a by-pass pipe comprising a check valve that prevents the flow of fuel back to the at least one fuel tank; opening an electrically controllable inlet valve of the high pressure pump; and operating the high pressure pump to suck fuel upstream of the high pressure pump. ### Claim 17 (depends on 1) The fuel system according to claim 1, wherein said means to suck fuel from the low-pressure circuit is arranged to suck fuel from the low-pressure circuit and the fuel is arranged to by-pass the at least one low-pressure fuel pump and at least one of the first or second fuel filters via the at least one by-pass pipe comprising the check valve that prevents the flow of fuel back to the fuel tank. ### Claim 18 (depends on 14) The internal combustion engine according to claim 14, wherein said means to suck fuel from the low-pressure circuit is arranged to suck fuel from the low-pressure circuit and the fuel is arranged to by-pass the at least one low-pressure fuel pump and at least one of the first or second fuel filters via the at least one by-pass pipe comprising the check valve that prevents the flow of fuel back to the fuel tank. ### Claim 19 (depends on 15) The vehicle according to claim 15, wherein said means to suck fuel from the low-pressure circuit is arranged to suck fuel from the low-pressure circuit and the fuel is arranged to by-pass the at least one low-pressure fuel pump and at least one of the first or second fuel filters via the at least one by-pass pipe comprising the check valve that prevents the flow of fuel back to the fuel tank. ### Claim 20 (depends on 16) The method according to claim 16, wherein said arranging the flow of fuel comprising arranging the flow of fuel to by-pass the at least one low-pressure fuel pump and at least one of the first or second fuel filters via the by-pass pipe comprising the check valve that prevents the flow of fuel back to the at least one fuel tank.